Disabling buttons via Sub

Hello!

I wrote following sub to disable a button

Sub DisableButton(ByRef b As Object)
b.ForeColor = 15
b.Enabled = False
End Sub

Then somewhere else in a different sub

...
Call DisableButton(CommandButton4)
...

I tried countless variations of parameters and stuff, but I cant get it to work. How do I call the disablebutton sub correctly?